Optimization method for developing spectral controlling cosmetics: Application for thermal barrier cosmetic

In this paper, a method of optimizing a thermal barrier cosmetic and spectral selective cosmetic by controlling the particle size and material is proposed as a countermeasure to heatstroke. The radiative properties of single cosmetic particles of a wide range of particle sizes and wavelengths in non-absorbing air were calculated in this study based on the Mie theory. Al₂O₃, TiO₂, Au, and Ag were used as the material of the cosmetic particle. The radiative property of a particle cloud in dependent scattering was calculated. The radiative transfer in the cosmetic layer was analyzed, and the spectral reflectance of the cosmetic layer on the human skin was calculated. A new parameter was defined to quantitatively evaluate the performance of the thermal barrier cosmetic and spectral selective cosmetic. For the thermal barrier cosmetic, the Al₂O₃ particle was determined to be suitable, and its size was optimized. For the spectral selective cosmetic, the Au particle was likewise determined to be suitable, and its size was optimized. Our cosmetics satisfied both aesthetic and thermal concerns.